DE 10 2004 032 826 A1 discloses a method for producing stampings in a die, in particular in a precision blanking die, by means of at least one punch, with which the stamping is pressed out of a material strip. This known method provides that the stamping, after being pressed out of the material strip, is pushed by this strip to a discharge facility. In the course of pressing out the stamping, the punch works together with a pressure pad in a die plate. When the die is opened, the pressure pad pushes the stamping as far as to the surface of the die plate, and the material strip is lifted off the die plate. The material strip is lifted a defined distance off of the die plate, this distance being equal to at least the thickness of the stampings.
Although this strategy known from the prior art prevents the precision blanking from being pressed back into the material strip, a state that is considered to be a drawback for precision blankings, this advantage is achieved at the expensive of relative movements inside the die interior perpendicular to the running direction of the material strip, as a result of which it is necessary to completely open the die, and at the same time it makes the construction of the die more complicated. The complete opening of the die demands a longer opening path, as a result of which the number of press strokes is limited. Therefore, this method known from the prior art cannot be used with high speed presses.
Other known solutions discharge the stampings through sorting devices (see DE 27 48 228 A1) or by blowing them out. In some cases the stampings are pressed back again into the material strip and discharged with the material strip. However, this pressing back has the drawback that the high cutting quality achieved by the precision blanking operation is significantly reduced. The roughness of the clean cut functional surfaces and their range of tolerance requirement suffer from being pressed back contrary to the original cutting direction, and the pressing out causes the quality to suffer significantly.
JP 11309522 A discloses a method for punching out stampings from a board shaped strip material, wherein in a first cutting step the stamping remains connected along its periphery to the strip material, and in a second step the finishing cut of the semi-finished product is performed with the main punch.
Even in this prior art method the die has to be completely opened, a requirement that limits the number of press strokes and restricts its use to low speed presses.